Clam shell pump housing defining passageways and a sealed pressure or vacuum chamber

ABSTRACT

A pump has a motor pump unit enclosed by clam shell housing sections. The pump moves a working fluid through the housing to an outside load. Each section has intake walls defining a portion of an intake chamber and outlet walls defining a portion of an outlet chamber. The intake walls of each section seal against one another to define a sealed intake chamber which is in communication with the intake port of the pump unit, and the outlet walls of each section seal against one another to define a sealed outlet chamber which is in communication with the outlet port of the pump unit.

CROSS-REFERENCE TO RELATED APPLICATION

This claims the benefit of U.S. Provisional Patent Application No.60/175,183 filed Jan. 10, 2000.

STATEMENT CONCERNING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

This invention relates to housings or cabinets for pumps such ascompressors or vacuum pumps. In particular, this invention concerns sucha pump in which clam shell halves of the housing form seals at theirabutting edges to define pressure or vacuum chambers or passagewayswithin the housing.

BACKGROUND OF THE INVENTION

In many applications, a compressor or vacuum pump is housed inside acabinet (a.k.a., housing), which may be of molded plastic. In the caseof a compressor, the compressor needs intake air, which must be drawn infrom outside of the housing and directed to the intake port of the pump,the pump compresses it, and delivers it to a pressurized exhaust port.Typically, tubing Is used to direct the output of the exhaust port to aport which is accessible by the user from outside of the housing. Theintake air delivered to the pump usually must be filtered, so that onlyfiltered air is delivered to the intake port, and tubing or passagewaysare required to communicate the filtered air to the intake port.

SUMMARY OF THE INVENTION

The invention provides an improvement to a pump having clam shellhousing sections in which each said housing section has one or morewalls which seal against one or more walls of the other housing sectionto define a sealed pressure or vacuum chamber within the walls when thehousing sections are brought together. The walls come together toprovide a seal all the way around the chamber, which may be an inletchamber, an outlet chamber, or a pressurized (including depressurized)passageway, so that a pressure difference can be contained in thechamber, either positive or negative. Thereby, additional tubing orpassageways in addition to the housing for routing the intake and outletof the pump are obviated.

In a preferred form, the walls are overmolded with an elastomericsealing material. The walls may seal against one another in end to endcontact, or a wall may seal against the side surface of another wall. Inthe latter case, it is preferred that the sealing edge of theelastomeric sealing material be tapered to make a good seal, and theunderlying edge of the wall may also be tapered to help reinforce thesealing material. Edge to side sealing is done with the exposed side ofthe sealing material facing the high pressure side, so that the pressurehelps establish the seal.

The chamber may be in communication with either the intake or outletport of the pump. At least one of the walls in each housing section maybe formed with a half-circular recess in an edge of the wall so that thehalf circular recesses come together to seal around a circular intake oroutlet port of the pump when the housing sections are brought together.A hole or tubular port may also be formed in one or more of the walls tocreate a means for entry of ambient air to the chamber, mainly for anintake chamber, or a port to which a tube could be connected, mainly foran outlet chamber.

The foregoing and other objects and advantages of the invention willappear in the detailed description which follows. In the description,reference is made to the accompanying drawings which illustrate apreferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of one clam shell half of a housingcontaining a compressor;

FIG. 2 is a top plan view of the clam shell half of FIG. 1;

FIG. 3 is a bottom plan view showing the other clam shell half whichmates with the clam shell half shown in FIGS. 1 and 2;

FIG. 4 is a sectional view from the plane of the line 4—4 of FIG. 2,drawn with both clam shell halves assembled together;

FIG. 5 is a cross-sectional view from the plane of the line 5—5 of FIG.2, drawn with the two clam shell halves assembled together;

FIG. 6 is a cross-sectional view from the plane of the line 6—6 of FIG.2, drawn with the two clam shell halves assembled together;

FIG. 7 is a cross-sectional view from the plane of the line 7—7 of FIG.2, drawn with the two clam shell halves assembled together;

FIG. 8 is a cross-sectional view from the plane of the 8—8 of FIG. 2,drawn with the two clam shell halves assembled together;

FIG. 9 is a cross-sectional view from the plane of the line 9—9 of FIG.2, drawn with the two clam shell halves assembled together; and

FIG. 10 is a top cross-sectional view illustrating the air flow pathsthrough the intake and exhaust chambers defined by the housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 illustrate one clam shell half 12 of a nebulizer housingand FIG. 3 illustrates the other clam shell half 14. The nebulizerincludes a motor pump unit 16 which has an inlet port 18 and an exhaustport 20. The inlet port 18 opens into and draws air from an intakechamber 22 and the exhaust port 20 opens into and expels pressurized airinto an exhaust chamber 24. Air is drawn into the intake chamber 22through a hole 26 in one of the walls of the chamber 22, and a filter(not shown) may be installed in or over the hole 26. Air is exhaustedfrom the exhaust chamber 24 through an outlet port 30 which is formed inone of the walls of the exhaust chamber 24 as shown in FIGS. 9 and 10.

Part of each chamber 22 and 24 is formed by the clam shell half 12 andthe other part of each chamber 22 and 24 is formed by the clam shellhalf 14. Together, walls of the clam shell halves 12 and 14 create thechambers 22 and 24, and the chambers 22 and 24 are sealed against therespective ports 18 and 20 so that the chambers 22 and 24 are sealedexcept at the respective ports 18, 26, and 20, 30.

The walls of the clam shell halves 12 and 14 which make up the chambers22, 24 are thin walled molded plastic sections which in each half areintegrally molded with the other walls of the half. The clam shellhalves 12 and 14 would typically be made of a relatively hard and stiffplastic material such as high impact polystyrene. The walls which makeup the chambers 22 and 24 would have a typical thickness of 0.090inches. The edges of the walls that make up the chambers 22, 24, wherethey abut all the way around the respective chamber 22, 24, cometogether to seal the interiors of the chambers 22, 24 against a pressuredifference. However, for the exhaust chamber 24, along wall 34, theedges do not abut, although a wall 36 of the clam shell half 14 abutsthe side surface of wall 34.

So that the abutments of the walls of the clam shell half 14 with thewalls of the clam shell half 12 may be sufficient so as to create a sealagainst a pressure difference between the chambers 22 and 24 andatmospheric pressure, at each interface between the walls of the halves12 and 14, the interfacing surfaces are coated with a relatively soft,e.g. 50 to 60 durometer, thermoplastic elastomer or thermoplastic rubber(TPR) such as Santoprene. This is preferably overmolded onto the edgesof the walls that create the seals for the chambers 22, 24. This can bedone in a two-shot injection molding process, either in which the harderplastic which makes up the majority of the halves 12 and 14 is firstmolded in one mold, and then the halves 12 and 14 are put in separatemolds to overmold the relatively softer elastomeric material, or inwhich the harder plastic is molded in one mold in one shot and thencores of the mold are retracted to make room for a shot of therelatively softer material over the edges of the walls that form thechambers 22 and 24.

As shown in FIG. 9, in the case of the seal between the walls 34 and 36,a single TPR gasket 40 is molded onto the edge of the wall 36 and has atapered configuration so as to generally match the curvature of thesurface of the wall 34 and thereby create a seal between the wall 36, towhich the gasket 40 is attached, and the wall 34 which abuts the gasket40. On the other side of the chamber 24, a gasket 44 is overmolded ontothe edge of wall 46 and a gasket 48 is overmolded onto the edge of wall50. The gaskets 44 and 48 abut each other to create a seal between them,and thereby create a seal between the walls 46 and 50. A gasketedinterface is provided all the way around each chamber 22 and 24.Thereby, the only inlet to chamber 22 is hole 26 and the only outlet isport 18, and the only inlet to chamber 24 is port 20 and the only outletis port 30. In normal operation, chamber 22 is subjected to quite lowpressure differences, being an intake chamber, with the only pressuredifference being created by a filter which may be installed in hole 26,but chamber 24 may be subjected to pressures on the order of about 15psi.

FIGS. 5 and 6 illustrate how seals are created around the ports 18 and20 of the motor pump unit 16. Semi-circles are formed in the walls ofthe two halves 12 and 14 which, when the edges of the semi-circularopenings are overmolded with the relatively soft gasket material,closely mate with the outside diameters of the ports 18 and 20 so as tocradle the ports. As an enhancement to the invention, rather thangaskets such as the gasket 44 and 48 meeting along a flat surface, oneof the gaskets 44, 48 may be formed with a pointed edge and the othergasket 44, 48 may be formed flat, or with a V-shaped groove to receivethe pointed edge to create a form fit, to thereby create a more reliableseal.

FIGS. 7 and 8 illustrate seals that are created for the intake chamber22. The above description for the seals of the exhaust chamber 24applies to the exhaust chamber 22 as well, although with different wallsand gasket edges meeting. In FIG. 7, mating overmolded gaskets areidentified by reference numbers 60; 62 and 64; 66. In FIG. 8, matingovermolded gaskets are identified by reference numbers 68, 70. In FIG.8, a relatively tall wall 52 has gasket material 56 at its end, which istapered, and the gasket material 56 is also tapered to press up againstthe side of wall 34 of the half 12. The tapering of the end of the wall52 helps stiffen the gasket 56 against bending to improve the sealagainst the curved surface of the wall 34 which is created by pressingthe gasket 56 against it.

The two cabinet halves 12, 14 are held together by any suitable means,such as snap fits, fasteners through holes 80, a combination of snapfits and fasteners, or any other suitable means.

Many modifications and variations to the preferred embodiment describedwill be apparent to those skilled in the art which will still embody theinvention. For example, a sealed passageway incorporating the inventioncould be made in any shape. Therefore the invention should not belimited to the preferred embodiment described.

1. In a pump having clam shell housing sections, the improvement Whereinsaid clam shell housing sections enclose a motor pump unit for pumping aworking fluid to be delivered to a load outside said housing sectionsand each said housing section has one or more walls which create a sealagainst one or more walls of another housing section to define a sealedpressure or vacuum chamber of the working fluid within said walls whensaid housing sections are brought together to enclose said motor pumpunit, wherein at least one of said walls has an edge which is overmoldedwith an elastomeric seal material.
 2. The improvement of claim 1,wherein said chamber is in communication with an intake port of saidpump.
 3. The improvement of claim 1, wherein said chamber is incommunication with an outlet port of said pump.
 4. The improvement ofclaim 1, wherein at least one of said walls includes at least a portionof an inlet hole formed therein.
 5. The improvement of claim 1, whereinat least one of said walls includes at least a portion of a port formedtherein.
 6. The improvement of claim 1, wherein walls of said housingsections mate in end to end contact to define at least part of saidchamber.
 7. In a pump having clam shell housing sections, theimprovement wherein said clam shell housing sections enclose a motorpump unit for pumping a working fluid to be delivered to a load outsidesaid housing sections and each said housing section has one or morewalls which create a seal against one or more walls of another housingsection to define a sealed pressure or vacuum chamber of the workingfluid within said walls when said housing sections are brought togetherto enclose said motor pump unit, wherein at least one of said walls ineach said housing section contains a half-circular recess in an edge ofsaid wall, and wherein said half circular recesses come together to sealaround a circular port of said pump when said housing sections arebrought together.
 8. In a pump having clam shell housing sections, theimprovement wherein said clam shell housing sections enclose a motorpump unit and each said housing section has one or more walls whichcreate a seal against one or more walls of another housing section todefine a sealed pressure or vacuum chamber within said walls when saidhousing sections are brought together to enclose said motor pump unit,wherein at least one wall of at least one of said housing sections sealsagainst a side surface of a wall of the other housing section to defineat least part of said chamber, wherein said at least one wall has atapered end.
 9. The improvement of claim 8, wherein said at least onewall is overmolded with an elastomeric sealing material.
 10. In a pumphaving clam shell housing sections, the improvement wherein said clamshell housing sections enclose a motor pump unit and each said housingsection has one or more walls which seal against one or more walls ofanother housing section to define a sealed pressure or vacuum chamberwithin said walls when said housing sections are brought together toenclose said motor pump unit, wherein at least one wall of at least oneof said housing sections seals against a side surface of a wall of theother housing section to define at least part of said chamber, whereinsaid at least one wall has a tapered end, wherein said at least one wailis overmolded with an elastomeric sealing material, wherein saidelastomeric sealing material tapers toward the tapered end of the atleast one wall and wherein the underlying at least one wall is alsotapered.
 11. A pumping unit comprising: a motor pump unit pumping aworking fluid through an intake port and an outlet port; first andsecond clam shell housing sections which enclose said motor pump unit,each said section having intake walls defining a portion of an intakechamber and outlet walls defining a portion of an outlet chamber;wherein said intake walls of said first section create a seal againstthe intake walls of the second section to define a sealed intake chamberfor the working fluid which is in communication with the intake port ofsaid pump; and wherein said outlet walls of said first section create aseal against the outlet walls of the second section to define a sealedoutlet chamber for the working fluid which is in communication with anoutlet port of said pump for delivering the working fluid to a loadoutside the housing sections.
 12. A pumping unit as claimed in claim 11,wherein a hole is formed in a wall of said intake chamber.
 13. A pumpingunit as claimed in claim 11, wherein an outlet port is formed in a wallof said outlet chamber.
 14. A pumping unit comprising: a motor pump unithaving an intake port and an outlet port; first and second clam shellhousing sections which enclose said motor pump unit, each said sectionhaving intake walls defining a portion of an intake chamber and outletwalls defining a portion of an outlet chamber; wherein said intake wallsof said first section seal against the intake walls of the secondsection to define a sealed intake chamber which is in communication withthe intake port of said pump; wherein said outlet walls of said firstsection seal against the outlet walls of the second section to define asealed outlet chamber which is in communication with an outlet port ofsaid pump; and wherein Intake walls of said first and second sectionsseal against an intake port of said pump and outlet walls of said firstand second sections seal against an outlet port of said pump.
 15. Apumping unit comprising: a motor pump unit pumping a working fluidthrough an intake port and an outlet port; first and second clam shellhousing sections which enclose said motor pump unit, each said sectionhaving intake walls defining a portion of an intake chamber and outletwalls defining a portion of an outlet chamber; wherein said intake wallsof said first section seal against the intake walls of the secondsection to define a sealed intake chamber for the working fluid which isin communication with the intake port of said pump; wherein said outletwalls of said first section seal against the outlet walls of the secondsection to define a sealed outlet chamber for the working fluid which isin communication with an outlet port of said pump for delivering theworking fluid to a load outside the housing sections; and wherein intakewalls of said first and second sections seal against one another in endto end contact.
 16. A pumping unit comprising: a motor pump unit pumpinga working fluid through an intake port and an outlet port; first andsecond clam shell housing sections which enclose said motor pump unit,each said section having intake walls defining a portion of an intakechamber and outlet walls defining a portion of an outlet chamber;wherein said intake walls of said first section seal against the intakewalls of the second section to define a sealed intake chamber for theworking fluid which is in communication with the intake port of saidpump; wherein said outlet walls of said first section seal against theoutlet walls of the second section to define a sealed outlet chamber forthe working fluid which is in communication with an outlet port of saidpump for delivering the working fluid to a load outside the housingsections; and wherein outlet walls of said first and second sectionsseal against one another in end to end contact.
 17. A pumping unitcomprising: a motor pump unit having an intake port and an outlet port;first and second clam shell housing sections which enclose said motorpump unit, each said section having intake walls defining a portion ofan intake chamber and outlet walls defining a portion of an outletchamber; wherein said intake walls of said first section seal againstthe intake walls of the second section to define a sealed intake chamberwhich is in communication with the intake port of said pump; whereinsaid outlet walls of said first section seal against the outlet walls ofthe second section to define a sealed outlet chamber which is incommunication with an outlet port of said pump; and wherein end edges ofintake and outlet walls of said first and second sections are overmoldedwith an elastomeric sealing material.